This invention relates to the use of microwave energy for the therapeutic treatment of a gland of the body and more particularly to an irregularly shaped microwave applicator positioned in the male rectum for the hyperthermia treatment of the prostate gland.
Medical practioners know that a patient with a cancerous tumor can be treated by a process which raises and maintains the temperature of the tumor to a predetermined value of about 43.degree. C. This treatment is generally referred to as hyperthermia. One method of hyperthermia utilizes microwave energy. The temperature of the tissue irradiated by the microwave energy is a function of the powder or intensity of the microwave signal applied to the body tissue. The depth of penetration of the microwave signal into the tissue is generally a direct function of the type of tissue and an inverse function of the frequency of the signal applied. The dimensions of the shape of the irradiated volume of tissue are dependent on the parameters, such as, the type of tissue, the frequency of the microwave signal, and the radiation pattern of the microwave signal.
The microwave irradiation may be controlled to elevate the temperature of a volume of tissue. It is desirable to elevate the temperature of the treated tissue to the hyperthermic range while maintaining the temperature of an untreated tissue, within the general environment of the treated tissue, approximately at the normal body temperature. Various systems that apply microwave energy to the surface of the body for the hyperthermia treatment of subcutaneous tissue are known. One such system is described in the aforementioned U.S. Pat. No. 4,190,053. Microwave coaxial applicators having relatively small dimensions may be used for positioning within the body for hyperthermia treatment of subcutaneous tissue. Such a coaxial applicator is described in aforementioned U.S. Pat. No. 4,204,549. If the subcutaneous tissue to be treated is of a substantial volume and internally located in the lower abdomen of a body, the use of microwave energy applied to the surface of the body or the use of a coaxial applicator having relatively small dimensions may not provide sufficient microwave energy to heat and thereby raise the temperature of the prostate gland to the hyperthermia range.
It is now recognized that the use of microwave hyperthermia and radiotherapy procedures may be advantageous used in combination with each other.
An apparatus is provided using microwave energy for the therapeutic and hyperthermic treatment of an internal body organ such as the male prostate gland. A microwave source supplies a microwave signal having a predetermined amplitude and frequency. An applicator is provided that applies the microwave signal within an internal body cavity, such as a rectum, such that the rectal wall in close proximity to the prostate gland receives preferential heating relative to the rectal wall positioned diametrically opposite the prostate gland. Temperature sensing means positioned on the periphery of the applicator provides an electrical signal indicative of the temperature of the wall of the rectum in close proximity to the prostate gland. Control means, responsive to the temperature signal, couple the microwave signal to the applicator when the temperature of the rectal wall in close proximity to the prostate gland is less than a predetermined temperature.